The Laplacian spectral radius of a finite graph is defined as the largest value of its Laplacian spectrum, i.e., the largest eigenvalue of the Laplacian matrix or largest root of the Laplacian polynomial. The ratio of the Laplacian spectral radius to algebraic connectivity is known as the Laplacian spectral ratio.

algebraic connectivity | Laplacian matrix | Laplacian polynomial | Laplacian spectral ratio | spectral radius

Pierre-Simon Laplace